handle data gas / data gas fees appropriately (#26)

Author: roberto-bayardo

accounts/abi/bind/backends/simulated.go

@@ -819,6 +819,7 @@ func (m callMsg) To() *common.Address          { return m.CallMsg.To }
 func (m callMsg) GasPrice() *big.Int           { return m.CallMsg.GasPrice }
 func (m callMsg) GasFeeCap() *big.Int          { return m.CallMsg.GasFeeCap }
 func (m callMsg) GasTipCap() *big.Int          { return m.CallMsg.GasTipCap }
+func (m callMsg) MaxFeePerDataGas() *big.Int   { return m.CallMsg.MaxFeePerDataGas }
 func (m callMsg) Gas() uint64                  { return m.CallMsg.Gas }
 func (m callMsg) Value() *big.Int              { return m.CallMsg.Value }
 func (m callMsg) Data() []byte                 { return m.CallMsg.Data }

consensus/misc/eip4844.go

@@ -71,3 +71,8 @@ func VerifyEip4844Header(config *params.ChainConfig, parent, header *types.Heade
 	}
 	return nil
 }
+
+// GetDataGasPrice implements get_data_gas_price from EIP-4844
+func GetDataGasPrice(excessDataGas *big.Int) *big.Int {
+	return FakeExponential(big.NewInt(params.MinDataGasPrice), excessDataGas, big.NewInt(params.DataGasPriceUpdateFraction))
+}

core/blockchain_test.go

@@ -3923,6 +3923,8 @@ func TestDataBlobTxs(t *testing.T) {
 		msg.Nonce = view.Uint64View(0)
 		msg.GasFeeCap.SetFromBig(newGwei(5))
 		msg.GasTipCap.SetFromBig(big.NewInt(2))
+		msg.MaxFeePerDataGas.SetFromBig(big.NewInt(params.MinDataGasPrice))
+		// TODO: Add test case for max data fee too low
 		msg.BlobVersionedHashes = []common.Hash{one, two}
 		txdata := &types.SignedBlobTx{Message: msg}
 

core/error.go

@@ -82,6 +82,10 @@ var (
 	// transaction with a tip higher than the total fee cap.
 	ErrTipAboveFeeCap = errors.New("max priority fee per gas higher than max fee per gas")
 
+	// ErrMaxFeePerDataGas is returned if the transaction specified a
+	// max_fee_per_data_gas that is below the current data gas price.
+	ErrMaxFeePerDataGas = errors.New("max data fee per gas too low")
+
 	// ErrTipVeryHigh is a sanity error to avoid extremely big numbers specified
 	// in the tip field.
 	ErrTipVeryHigh = errors.New("max priority fee per gas higher than 2^256-1")

core/state_transition.go

@@ -23,7 +23,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	cmath "github.com/ethereum/go-ethereum/common/math"
-	//	"github.com/ethereum/go-ethereum/consensus/misc"
+	"github.com/ethereum/go-ethereum/consensus/misc"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -72,6 +72,7 @@ type Message interface {
 	GasPrice() *big.Int
 	GasFeeCap() *big.Int
 	GasTipCap() *big.Int
+	MaxFeePerDataGas() *big.Int
 	Gas() uint64
 	Value() *big.Int
 
@@ -162,25 +163,22 @@ func IntrinsicGas(data []byte, accessList types.AccessList, isContractCreation b
 		gas += uint64(len(accessList)) * params.TxAccessListAddressGas
 		gas += uint64(accessList.StorageKeys()) * params.TxAccessListStorageKeyGas
 	}
-	// TODO
-	//if rules.EIP4844 {
-	//gas += uint64(blobCount) * getBlobGas(blockExcessBlobs)
-	//}
 	return gas, nil
 }
 
 // NewStateTransition initialises and returns a new state transition object.
 func NewStateTransition(evm *vm.EVM, msg Message, gp *GasPool) *StateTransition {
 	return &StateTransition{
-		gp:        gp,
-		evm:       evm,
-		msg:       msg,
-		gasPrice:  msg.GasPrice(),
-		gasFeeCap: msg.GasFeeCap(),
-		gasTipCap: msg.GasTipCap(),
-		value:     msg.Value(),
-		data:      msg.Data(),
-		state:     evm.StateDB,
+		gp:               gp,
+		evm:              evm,
+		msg:              msg,
+		gasPrice:         msg.GasPrice(),
+		gasFeeCap:        msg.GasFeeCap(),
+		gasTipCap:        msg.GasTipCap(),
+		maxFeePerDataGas: msg.MaxFeePerDataGas(),
+		value:            msg.Value(),
+		data:             msg.Data(),
+		state:            evm.StateDB,
 	}
 }
 
@@ -206,21 +204,35 @@ func (st *StateTransition) to() common.Address {
 func (st *StateTransition) buyGas() error {
 	mgval := new(big.Int).SetUint64(st.msg.Gas())
 	mgval = mgval.Mul(mgval, st.gasPrice)
-	balanceCheck := mgval
-	if st.gasFeeCap != nil {
-		balanceCheck = new(big.Int).SetUint64(st.msg.Gas())
-		balanceCheck = balanceCheck.Mul(balanceCheck, st.gasFeeCap)
-		balanceCheck.Add(balanceCheck, st.value)
+
+	dgval := new(big.Int)
+	if st.evm.ChainConfig().IsSharding(st.evm.Context.BlockNumber) {
+		// add in fee for eip-4844 data blobs if any
+		dgval.Mul(misc.GetDataGasPrice(st.evm.Context.ExcessDataGas), st.dataGasUsed())
+	}
+
+	balanceCheck := new(big.Int)
+	if st.gasFeeCap == nil {
+		balanceCheck.Set(mgval)
+	} else {
+		balanceCheck.Add(st.value, dgval)
+		// EIP-1559 mandates that the sender has enough balance to cover not just actual fee but
+		// the max gas fee, so we compute this upper bound rather than use mgval here.
+		maxGasFee := new(big.Int).SetUint64(st.msg.Gas())
+		maxGasFee.Mul(maxGasFee, st.gasFeeCap)
+		balanceCheck.Add(balanceCheck, maxGasFee)
 	}
+
 	if have, want := st.state.GetBalance(st.msg.From()), balanceCheck; have.Cmp(want) < 0 {
 		return fmt.Errorf("%w: address %v have %v want %v", ErrInsufficientFunds, st.msg.From().Hex(), have, want)
 	}
 	if err := st.gp.SubGas(st.msg.Gas()); err != nil {
 		return err
 	}
 	st.gas += st.msg.Gas()
-
 	st.initialGas = st.msg.Gas()
+
+	mgval.Add(mgval, dgval) // both regular gas fee and data gas fee need to be deducted
 	st.state.SubBalance(st.msg.From(), mgval)
 	return nil
 }
@@ -270,6 +282,13 @@ func (st *StateTransition) preCheck() error {
 			}
 		}
 	}
+	if st.evm.ChainConfig().IsSharding(st.evm.Context.BlockNumber) {
+		dataGasPrice := misc.GetDataGasPrice(st.evm.Context.ExcessDataGas)
+		if dataGasPrice.Cmp(st.maxFeePerDataGas) > 0 {
+			return fmt.Errorf("%w: address %v, maxFeePerDataGas: %v dataGasPrice: %v", ErrMaxFeePerDataGas,
+				st.msg.From().Hex(), st.maxFeePerDataGas, dataGasPrice)
+		}
+	}
 	return st.buyGas()
 }
 
@@ -291,7 +310,9 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 	// applying the message. The rules include these clauses
 	//
 	// 1. the nonce of the message caller is correct
-	// 2. caller has enough balance to cover transaction fee(gaslimit * gasprice)
+	// 2. caller has enough balance to cover:
+	//       Legacy tx: fee(gaslimit * gasprice)
+	//       EIP-1559 tx: tx.value + max-fee(gaslimit * gascap + datagas * datagasprice)
 	// 3. the amount of gas required is available in the block
 	// 4. the purchased gas is enough to cover intrinsic usage
 	// 5. there is no overflow when calculating intrinsic gas
@@ -402,3 +423,13 @@ func (st *StateTransition) refundGas(refundQuotient uint64) {
 func (st *StateTransition) gasUsed() uint64 {
 	return st.initialGas - st.gas
 }
+
+func (st *StateTransition) dataGasUsed() *big.Int {
+	dataGas := new(big.Int)
+	l := int64(len(st.msg.DataHashes()))
+	if l != 0 {
+		dataGas.SetInt64(l)
+		dataGas.Mul(dataGas, big.NewInt(params.DataGasPerBlob))
+	}
+	return dataGas
+}

core/tx_pool.go

@@ -54,7 +54,7 @@ const (
 
 	// txWrapDataMax is the maximum size for the additional wrapper data,
 	// enough to encode a blob-transaction wrapper data (48 bytes for commitment, 4 for offset, 48 for a commitment)
-	txWrapDataMax = 4 + 4 + params.MaxBlobsPerTx*(params.FieldElementsPerBlob*32+48)
+	txWrapDataMax = 4 + 4 + params.MaxBlobsPerBlock*(params.FieldElementsPerBlob*32+48)
 )
 
 var (

core/types/data_blob.go

@@ -481,7 +481,7 @@ func (b *BlobTxWrapData) verifyVersionedHash(inner TxData) error {
 	if !ok {
 		return fmt.Errorf("expected signed blob tx, got %T", inner)
 	}
-	if a, b := len(blobTx.Message.BlobVersionedHashes), params.MaxBlobsPerTx; a > b {
+	if a, b := len(blobTx.Message.BlobVersionedHashes), params.MaxBlobsPerBlock; a > b {
 		return fmt.Errorf("too many blobs in blob tx, got %d, expected no more than %d", a, b)
 	}
 	if a, b := len(b.BlobKzgs), len(b.Blobs); a != b {

core/types/transaction.go

@@ -30,6 +30,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
@@ -403,13 +404,27 @@ func (tx *Transaction) To() *common.Address {
 	return copyAddressPtr(tx.inner.to())
 }
 
-// Cost returns gas * gasPrice + value.
+// Cost returns (gas * gasPrice) + (DataGas() * maxDataFeePerGas) + value.
 func (tx *Transaction) Cost() *big.Int {
 	total := new(big.Int).Mul(tx.GasPrice(), new(big.Int).SetUint64(tx.Gas()))
 	total.Add(total, tx.Value())
+	dataGasFee := tx.DataGas()
+	dataGasFee.Mul(dataGasFee, tx.MaxFeePerDataGas())
+	total.Add(total, dataGasFee)
 	return total
 }
 
+// DataGas implements get_total_data_gas from EIP-4844
+func (tx *Transaction) DataGas() *big.Int {
+	r := new(big.Int)
+	l := int64(len(tx.DataHashes()))
+	if l != 0 {
+		r.SetInt64(l)
+		r.Mul(r, big.NewInt(params.DataGasPerBlob))
+	}
+	return r
+}
+
 // RawSignatureValues returns the V, R, S signature values of the transaction.
 // The return values should not be modified by the caller.
 func (tx *Transaction) RawSignatureValues() (v, r, s *big.Int) {

light/txpool.go

@@ -378,7 +378,7 @@ func (pool *TxPool) validateTx(ctx context.Context, tx *types.Transaction) error
 	}
 
 	// Transactor should have enough funds to cover the costs
-	// cost == V + GP * GL
+	// cost == V + GP * GL + DGP * DG
 	if b := currentState.GetBalance(from); b.Cmp(tx.Cost()) < 0 {
 		return core.ErrInsufficientFunds
 	}
@@ -389,7 +389,6 @@ func (pool *TxPool) validateTx(ctx context.Context, tx *types.Transaction) error
 		EIP2028:   pool.istanbul,
 		EIP4844:   pool.eip4844,
 	}
-	// TODO: Check DataGas
 	gas, err := core.IntrinsicGas(tx.Data(), tx.AccessList(), tx.To() == nil, rules)
 	if err != nil {
 		return err

params/protocol_params.go

@@ -158,20 +158,14 @@ const (
 	RefundQuotient        uint64 = 2
 	RefundQuotientEIP3529 uint64 = 5
 
-	// Fixed cost for sending a data blob.
-	BlobGas uint64 = 120000
-
-	MaxDataGasPerBlock   = 1 << 21
-	DataGasPerBlob       = 1 << 17
-	MaxDataBlobsPerBlock = MaxDataGasPerBlock / DataGasPerBlob
-
-	TargetDataGasPerBlock = 1 << 20
-
-	MaxBlobsPerTx                 = 2
-	MaxBlobsPerBlock              = 16
-	TargetBlobsPerBlock           = 8
-	FieldElementsPerBlob          = 4096 // each field element is 32 bytes
-	GasPriceUpdateFractionPerBlob = 64
+	// stuff from EIP-4844
+	FieldElementsPerBlob       = 4096 // each field element is 32 bytes
+	MaxDataGasPerBlock         = 1 << 21
+	DataGasPerBlob             = 1 << 17
+	TargetDataGasPerBlock      = 1 << 20
+	MinDataGasPrice            = 10e8
+	DataGasPriceUpdateFraction = 8902606
+	MaxBlobsPerBlock           = MaxDataGasPerBlock / DataGasPerBlob
 
 	BlobVerificationGas      uint64 = 1800000
 	BlobCommitmentVersionKZG uint8  = 0x01